Japanese whaling harpoon ship offloads a minke whale onto the Japanese whaling factory ship the Nisshin Maru in the Southern Ocean in February 2013. Photo: Glenn Lockitch/Sea Shepherd

Tokyo is bidding for the multibillion-dollar contract to build Australia's fleet of 12 submarines to enhance what Japan's Prime Minister Shinzo Abe has called a "special relationship".

Anti-whaling activists Sea Shepherd had attempted to disrupt Japan's 115-day whale hunt over the summer, but said in February the group's vessel Steve Irwin had been unable to locate the four-ship fleet.

The Japanese whaling fleet operating in the Southern Ocean in 2013.
Photo: Glenn Lockitch/Sea Shepherd

The Turnbull government flagged the prospect of legal action in December, but Japan's decision to withdraw from the court's jurisdiction has complicated any response, with arbitration under the law of the sea understood to also be considered.

Don Rothwell, an international law specialist from the Australian National University, said the next confrontation with Japan was likely to be at the International Whaling Commission in October.

"The Commission meeting this year could prove to be quite pivotal for not only legal but diplomatic responses," Professor Rothwell said.

Ms Bishop said Australia would continue efforts in the International Whaling Commission to "strongly oppose commercial whaling and so-called 'scientific' whaling, uphold the moratorium on commercial whaling, and to promote whale conservation".